Biology 1010
Professor Harvey
April 30, 2014 It’s crazy to think about how not too long ago the mystery of a woman having two or more babies at once was completely a miracle, and now it’s just another part of the evolution and life cycle. The concept of twins has been around since the idea of genetics and biology has been discovered. As evolution has progressed we have seen a change in the gene pool and this has resulted in mutations and the perception of twins. As time has proceeded twins have become more common in society. Often people say that they would love to have twins or they would have loved to be a twin. As you can see presented in the graph above twins have been on the rise since 1990 and they are continuing to grow in population. There are many different types of twins in the world today. The ones that are most common to society are Identical, Fraternal, and Siamese twins. Although twins are conceived at the same time and are in utero together, not all are identically the same and there are many similarities and differences between them. Actually most common among twins is either extreme similarity or extreme dissimilarity. The first type of twins is identical twins and this means that they are genetically identical. The DNA sequences of identical twins are almost exactly the same, and this is why they look alike. They only use one fertilized egg that then splits into two and these twins can only be the same sex (Meyers 2004). These children have the same genes but they do not necessarily have the same number of those genes. The most common attributes with these twins is that they share the same birthdate, blood type and physical appearance in some rare cases they can even have different birthdays, sometimes the next day or in other circumstances they can be weeks or months apart. Even though people tend to think of twins as being identical only 1 out of every 250 pregnancies are
References: 1.Facts About Twins [Internet]. [UMMC]. University of Maryland Medical Center; 2014 [cited 2014 April 30]. http://umm.edu/programs/conjoined-twins/facts-about-the-twins 2.Martin JA, Hamilton BE, Osterman MJK. Three decades of twin births in the United States, 1980–2009. NCHS data brief, no 80. Hyattsville, MD: National Center for Health Statistics. 2012. 3.Meyers, David G. 2004. Psychology: Tenth Edition in Modules. New York (NY); Worth Publishers. 135 p. 4.Paternity Testing: Twins With Different Fathers [Internet]. [DDC] DNA Diagnostics Center; 2008 [cited 2014 April 30]. http://www.dnacenter.com/science-technology/articles/twins-different-fathers.html 5.What are conjoined Twin? [Internet]. [SCHRF]. Seattle Childrens Hospital Research Foundation; 2014 [cited 2014 April 30]. http://www.seattlechildrens.org/medical-conditions/chromosomal-genetic-conditions/conjoined-twins/